Such a device is known from practice and is, for instance, supplied by the firm Adams Paukenfabriek B. V., Thorn, the Netherlands.
The known device comprises a single unitary link, which, at a first side is provided with a pivot point and at an opposite, second side is provided with engagement means for an operating member, while between the first and the second end thereof coupling means are provided in the form of a pin having screw thread, for coupling the connecting means to the skin. The link is suspended in the first pivot point, with the coupling means being provided at a distance from the pivot point. During use, the coupling pin extends approximately vertically and is pulled in upward direction under the influence of the tension of the skin. Energization of the operating means causes the link to pivot around the pivot point, so that the coupling means are pressed downwards. This increases the tension of the skin, as a result of which, for instance, the pitch of the instrument is raised. Moreover, the pitch can be influenced by adjusting the pivot point in vertical direction, in such a manner that the link will pivot approximately about the engagement means for the operating member, which also brings about a movement in vertical direction of the coupling means.
The drawback of this known device is that a relatively large force is required for displacing the coupling means, in particular in the case of relatively high tension of the skin. This is disadvantageous, since it adversely affects the ease with which the instrument can be used. Moreover, due to the high forces that occur, the frame of the instrument is subject to a high load. In addition, there is the drawback that when the instrument is played, the skin will be displaced relative to the frame, in a direction other than intended for setting the tension of the skin. A further drawback of this known device is that due to the high forces that occur, distributed unevenly over the frame, different vibrations will occur in different parts of the frame, which adversely affects the resulting tones produced by the instrument, in particular in the high registers, in respect of both tonal purity and the duration of the tone.